1. Field of the Invention
The present invention relates to a technology for controlling a device in turning the device on and off through a network.
2. Description of the Related Art
A technology for remotely booting an information processor such as a personal computer (PC) from an external device through a local area network (LAN) has been developed. Such a technology is disclosed in, for example, “Magic Packet™ Technology”, searched on Feb. 6, 2003, <URL:http://www.amd.com/gb-uk/ConnectivitySolutions/ProductInformation/0,50—2330—2403—2420^2481,00.html>, “Building a Managed Computing Environment”, searched on Jun. 18, 2003, <URL:http://www.intel.com/network/connectivity/resources/do c_library/white_papers/solutions/managed_environment.htm>, and “Wake up to Wake-on-LAN”, searched on May 13, 2003, <URL:http://www.networking.ibm.com/eji/ejiwake.html>. For example, FIG. 6 is a block diagram of a conventional LAN card that enables a remote boot of a main unit. A LAN card 60 is connected to a power supply unit 30 in the main unit with a three-pin connector 20. Thus, a remote boot of a main unit 6 of a PC through the LAN is enabled. A PCI2.2-compliant PCI (peripheral component interconnect) bus can be used instead of the connector 20.
The LAN card 60 includes a power controller 600. When receiving a boot packet for instructing a boot of the main unit 6, the power controller 600 outputs a boot signal to the power supply unit 30. The power controller 600 is supplied with power from the power supply unit 30 through the connector 20.
The power controller 600 includes an analog receiver 610 and a protocol analyzer 620. The analog receiver 610 receives an analog signal from the LAN and converts the analog signal into digital data to transmit to the protocol analyzer 620.
The protocol analyzer 620 analyzes the digital data. The protocol analyzer 620 includes a boot packet detector 621 that detects a boot packet. The boot packet detector 621 detects the boot packet in the digital data, and outputs a boot signal to the power supply unit 30.
The main unit 6 can be remotely booted through the LAN in such a manner that the power controller 600 detects the boot packet and outputs the boot signal for turning on the power for the main unit 6, to the power supply unit 30. In other words, an external device connected to the main unit 6 through the LAN can remotely boot the main unit 6 by transmitting the boot packet to the main unit 6.
In the conventional technologies, however, a device cannot be controlled to be shut down remotely from an external device. To shut down the device, it is necessary to use a shutdown function provided by an operating system in the device.
If the operating system is out of control, for example, due to a hang up of the device, the device cannot be remotely shut down.